The Sea Scull panels

Almost every stitch and glue boat starts off with

• scarphing 4x8 plywood into bigger sheets,
• laying out the side and bottom panels,
• cutting the side and bottom panels,
• going back to the lumber store and buying more plywood because you screwed up,
• re-scarphing,
• re-cutting, and
• coating the panels.

Makita 4 3/8 power planer
with John Henry scarphing jig

I scarphed the Sea Scull panels with my Makita 4-3/8-inch power planer with John Henry scarphing jig.








Makita 4 3/8 power planer
with John Henry scarphing jig







An 8 on 1 scarph in 5mm-thick RevolutionPly will be a scarph that is
 

5mm RevolutionPly scarphed

5mm x 8 = 40mm = 1 9/16 inches wide

Since the planer blade is 4 3/8 inches wide, I can stack two sheets of RevolutionPly, being alert as to which face to scarph, and scarph them both at once.

Although I scarphed the entire 4-foot of the stain test panels, I will only use the unstained portions.





Scarphed panels glued and clamped.

The scarphed panels are then glued together to make longer sheets. Notice the top panel in the distance of the photo. Both ends are bent up while the scarph epoxy cures. I think this resulted in permanent warping of the panel, rendering it unusable. I had to scarph and glue another.











Laying out the design on the panels

After the scarph joints have cured, the clamps can be removed. Some sanding may be needed to fair the excess epoxy that oozed out of the scarph joint.

Then the measurements from the boat design can be layed out on the panels for cutting.













Chalk line down center of bottom panel

I struck a chalk line to create baseline for laying out station and offset points.













This RevolutionPly plywood is challenging. During the stain test I learned that the surface veneers are not well bonded to the plys beneath. Then I learned that it warps easily.

And now this...

Void in 5mm RevolutionPly

While laying out the stations and offsets on the bottom panel, I noticed a hump in the plywood. I thought it was a wood chip underneath but no. It was a void in the plywood plys. I got out my Dremel tool and began playing dentist. (Playing dentist = removing the unbonded plys, chasing the void, and asking the plywood questions while my fingers are in its mouth). The void is a manufacturing defect at a joint in one of the inner plys. The sawtooth pattern is a joint in an internal ply. The red is probably the glue that should hold the plies together, but in this case has failed. Oh well, I'll just fill it with epoxy, The Mo 'Poxy, the stronger the boat.

Side panels clamped together for cutting.
Void in 5mm RevolutionPly about 1/3 of the way down
the bottom panel.

Both side panels can be cut at once by clamping them back to back and cutting. Face them inside-to-inside or outside-to-outside so they are mirror images of each other and not exact duplicates. Otherwise, you will cut one of the panels inside-out.



Panels cut to final shape

Instructions for S&G boats often say to use a long flexible piece of wood to connect the station/offset points in a smooth curve. Then they say to cut ouside of the curve and sand to the curve as is if this curve is something extra special. I find this strange because none of these curves are final edges. All of these curves will be hidden. The bottom of the side panels and the edge of the bottom panel will be joined to form the chines. The inside of the chines will be filleted with thickened epoxy and covered with heavy fiberglass. The outside of the chines will be sanded round and covered with heavy fiberglass. The top of the side panels will be sandwiched between the inwhales and the rubrails which will all be sanded flush after gluing.

These curves aren't so special.

I connect the dots with straight lines and cut to the lines with a jig saw.



Void filled with thickened epoxy

After cutting the panels, I filled the void with epoxy thickened with silica powder and wood flour. The epoxy was levelled with a dry-wall blade.

 

Panels being coated.
Bottom with dry fiberglass. Side panel coated. Side panel uncoated

I coated the inside face of the panels with unthickened epoxy. The inside face of the bottom gets fiberglass saturated with epoxy since it will be stepped on. I used several scraps of fiberglass with lap joints for the inside of the bottom since it will be painted and the lap joints unseen.

Competed epoxy coating of panel insides

After the epoxy/fiberglass has cured, another layer of epoxy is added to fill the weave of the fiberglass.















Epoxy coating of test panels

While playing with epoxy, I coated a couple of test panels out of scrap RevolutionPly, for future testing of paints.

Hand sanding of side panel exteriors

Since the exterior of the side panels will be finished in their natural color, I hand-sanded them with 220 grit sand paper.














Dry lay-up of epoxy and fiberglass

After vacuuming to remove the sanding dust, I coated the exterior of the side panels with fiberglass saturated with epoxy, using the dry lay-up method.















Completed panels

These are the completed panels. All faces are coated except the exterior of the bottom. It will be coated later.

Notice that the epoxy does not extend all the way to the edges of the panels. That is because there will be gluing at these locations in the future.











Coated scarph joint in exterior face of RevolutionPly

For all of the trouble that RevolutionPly has been, it looks nice when finished.
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...If finished.